1. Field of the Invention
The present invention relates to an image determining method and the like that determine a pictured status of a predetermined subject in video and an image shot by a camera, and, more particularly relates to an image determining method and an image determining apparatus capable of selecting optimum video data and image data even when there is other structures between a camera and a subject by taking the structures into consideration, and a recording medium having recorded therein a program for causing a computer to execute the image determining method.
2. Description of the Related Art
Conventionally, when a user of video data of a predetermined subject (hereinafter, simply “user”) wants to obtain video data and an image of the subject, the user shoots the subject from various directions by using a plurality of cameras set at different positions, views and selects optimum data, that is, data of the best pictured status of the subject from the group of shot video data pieces and images by the user himself, and uses the selected video and image data.
However, according to the above method, if the number of pieces of video data and image data of the subject shot by the cameras increases, the user needs to view and check the video and image data one by one and select an optimum image frame of the video data and optimum image data (hereinafter, simply “image”) by the user himself. Therefore, there is a problem that a burden on the user is heavy.
To reduce the burden on the user, therefore, a technique enabling automatic selection of an optimum piece of video and image data, using a camera position and direction and the position of the subject, based on a shooting space and the position of the subject is disclosed (for example, see Japanese Patent Application Laid-open No. 2001-34250 and Japanese Patent Application Laid-open No. 2003-179908). According to this technique, as shown in FIG. 22, a shooting space of the image shot by the camera A is defined as an elliptic-cone or quadrangular-pyramid space which outspreads from the position of the camera A, i.e., the vertex, centering on the shooting direction, so as to cover the camera's angle of view calculated based on a focal length. Subjects A and B in the shooting space are determined to appear in the image, and subject C out of the space is determined not.
As a method for determining the pictured status of the video and image, a distance from the camera A is respectively calculated relative to the subjects A and B, which have been determined to appear in the image of the camera A, and the subject B closer to the camera A than the subject A is determined to be well-pictured and the subject A is determined not to be well-pictured.
As another method for determining the pictured status of the video and image, there is a method in which among the subjects A and B present in the shooting space of the camera, subject A particularly close to the central axis of the elliptic cone or the quadrangular pyramid of the shooting space is determined to be well-pictured.
However, in the above conventional technique, there is a problem that the optimum video and image data cannot be always selected.
Because, as shown in FIG. 23, when there is a group of other structures respectively between the camera A and the subjects A and B, the subjects A and B are hidden by the group of other structures, and the camera A cannot shoot the subjects A and B appropriately. The conventional method, however, still erroneously selects the image shot by the camera A as the optimum image data with respect to the subjects A and B.
The erroneous selection also occurs in the method for determining the pictured status of the subject. Thus, the conventional technique cannot appropriately select the optimum data because it does not take into consideration other structures present between the camera and the subject.
Thus, it is important to allow for an automatic selection of the optimum image data, taking other structure or the like into consideration, even when there is other structure or the like between the camera and the subject.